Background: Expert human resources have a key role in development of the community; among the multiple factors influencing this development, the community leaders who are organizing the resources have the most prominent role. This study aimed to investigate the relationship of leadership style with job satisfaction and happiness among the health personnel of the Oil Industry Health Organization. Methods: The present applied study is a descriptive-analytical one which was implemented cross- sectionally on all 290 health personnel of the Oil Industry working in the Provinces of Markazi and Lorestan. The Fiedler Leadership Style questionnaire, Chrome's Job Satisfaction questionnaire, and Oxford Happiness questionnaire were used to gather the data. The data were then analyzed by Pierson's correlation test. Results: The correlation-oriented leadership (66.15 ± 22.04) was the dominant leadership style which had a significant association with job satisfaction (176.58 ± 32.49) of the rehabilitation, treatment, and care staffs of oil industry in Markazi and Lorestan provinces, (r = 0.579, p < 0.01). Conclusion: The relationship-oriented leadership style has a significant association with job satisfaction. So, designing and implementing interventions to promote relationship – oriented style of leadership is recommended. More extended studies in the similar contexts could be helpful.